Brand new to knitting, but picking it up quickly although patterns still confuse me. I was wondering how to knit a circle (i.e. a hat brim or round pot holder). And can circular needles be used to do circles or just tubes? Thank you so much for the help!
Circular needles can be used to knit flat items, especially those with a large number of stitches, such as throws or shawls. To knit in the round, cast on enough sts to fit around the needle and just begin knitting, joining the 2 ends of the CO. For things that start with just a few sts, you would need to use the Magic Loop method or double pointed needles to start the item in the center, like a round pot holder. Take a look at the videos for knitting in the round on the Advanced techniques page. And welcome to Knitting Help!
flat circles are often done on circular needles, starting with a small amuont of stitches and increasing out in such a way that the knitting doesnt realy form a tube but a flat piece (look at some round shawl patterns, for example the Egeblad KAL in the knit-along forum).
Similar techniques can also be used to make hat brims, it is all to do witht he ration of incrases to stiotches i think.
Lots of ways!
Using circ’s or dpn’s:
you can knit a flat (disk) circ by starting with X (4 0r 8 stitches) and every time you double the rounds, double the stitches
–that is, cast on 4, R1: K4, R2 (number of rounds has doubled–so double # of stitches) K1,YO, (4 times/8 stitches.
R3 knit
R4: (once again, you’ve doubled (from 2 to 4) so increase (double stitches, K1, Yo, (8 times!/16 stitches
R 5, Knit
R6: K
R7: knit
R8 (double from 4!–so double stitch count–K1, Yo, (16 times/32 stitches)
proceed, increasing again on R16, R32, R64, etc
(if you start with 8 you’ll have the same numbers of stitches, but they will be on different row numbers)
OR follow this pattern:
cast on 8,
R1: knit
R2: K1, Yo (8 times) (16 stitches
R3: Knit
R4: K2, Yo (8 times)(24 stitches)
R5: Knit
R6, K3, Yo (8 times–32 stitches)
(continue in like manner, 8 evenly spaced increases every other round)
But you can also knit a disk flat on straight needles
cast on 24,
r1: K20, wrap and turn
R2: Knit every stitch
R3: Knit 16, wrao and turn
R4: knit every stitch
R5: Knit 12, wrap and turn
R6: knit every stitch
R8 Knit 8, wrap and turn
R9: Knit 4 wrap and turn
R10, Knit
R11: Knit across row, picking up all the wraps as you go.
R12, Knit across row.
Start again with r1: repeat until you have knit enough wedges to make a disk bind off, and sew cast off edge to cast on edge!
but you can also knit rounds (tubes)
and again there are several ways…
the classic knit in round (on DPN’s, or circs (2 circ’s or 1)
you can also knit in round (tube ) by casting on an even number and work on straight needles!
*K1, bring yarn forward as if to purl, slip 1, bring yarn to back as to knit.
repeat this pattern across row, and repeat for every row. (simple double knitting)
depending on your cast on/set up this will be a closed or open ended tube.
My head is spinning a little trying to figure out how to read patterns. I have a little idea on what the abbreviations mean; I think. Thank you so much for your help. 
Learning to read patterns is a second skill (knitting is 1 skill, reading patterns is an associated skill.)
[B]1-[/B]I use R# for round/row.
[B]2[/B]–K =knit, P=Purl,
YO/Yo=Yarn OVER an increase that leaves a HOLE–you wrap the yarn over the needle to make a “half stitch” (top of stitch) in R1, In R2 you knit into the half stitch --the half stitch leaves a hole behind
[B]3-[/B]-k2tog (P2tog) is a decrease (Knit(Purl) 2 stitches together
this decrease makes knitting lean to right
[B]4-[/B]-ssk =slip 1, slip 1, Knit the 2 slipped stitches together.
the slipping the 2 stitches ‘turns them round’ so this decrease leans to left.
[B]5-[/B]-wrap and turn.
this is a strange directions. you knit (some of the stitches in a row… NOT all of them) then you the next stitch onto right needle, pass the yarn between the needles, and return the stitch to left needle–(that is the wrap part!) if you think of a stitch as a V a wrap is <!
Turn. after wrapping, turn the work (pretend you are at the end of the row!)
Knit or purl as directed.
[B]6[/B]–Pick up wraps… the < stitch can be picked up and put on to a the needle (In stocking knit, the wrap Must be picked up and placed behind the wrapped stitch --but in garter is its less critical)
then Knit the wrap and the wrapped stitch together, (just like a K2tog.)
(add learning how to pick up stitches, with these 6 bits of pattern shorthand, you can knit a sock!)
there are other short hands (M1,(make 1 /an increase) PM(place Marker) (and SM (slip marker, and RM (remove marker) and a whole bunch of cable short hand…
but with time you’ll learn to read knitting patterns as easy as you read a telephone book, or the TV listing, or recipe directions…
there are places where there are list of diirectons (the Encyclopedia of Knitting, for 1, but there are on line places)
find one (check out knitting books in the library) copy it (its perfectly legal to copy a page (up to 10 pages!) in a library book)
LAMINATE IT and keep it with your knitting (if you are smart, make a half dozen copies… some full sized (easy to read) some reduced size ones (easy to tuck into knitting bag)
get stuck some place where you can’t knit for a short while?
read the KEY TO ABREVIATIONS… learn them!