Just want to make sure I'm clear

Okay, new to knitting and all, all I’ve made are scarfs-and 3 at that- and I found a project that has ben identified as somewhat beginner, but I’m pretty sure I’m going to need a translator. I mean, I can look it up in the glossary, but I don’t understand the process of what its actually telling me to do… so I’m just going to put it here and I guess ask questions? Idk…I’ll point things out…I hope.

Body: CO 18 sts using #6 needles and Rowan All Seasons Cotton in gray. Work 18 rows in [U]St st[/U], [U]then cut yarn and run through all sts, pulling together tightly[/U].

Ears [make 2]: CO 8 sts using #6 needles and gray yarn.
Work 5 rows in St st.
[U]Work 2 sts together at the end of each of the next 3 rows[/U]. 2 sts remaining. Work those 2 sts together and pull yarn through last st.
Make another ear in the same way.

Trunk: CO 13 sts using #6 needles and gray yarn. [U]Work in garter stitch for 5 rows[/U] and then [U]BO[/U] all. Join cast on and bound off edges together.

Making up: Join back seam of puppet using [U]mattress stitch [/U]and turn right side out. Place trunk in center of puppet and attach firmly. Attach ears to each side of the top of the puppet with the wrong side facing. Using black cotton, sew 2 eyes above the trunk. [An alternative to this is to use toy eyes that you can buy from a craft shop and attach to puppet. These are not suitable for children under 3 years, so if you are making the puppets for young children it is best to sew on the eyes.]

The underlined parts are the processes I don’t know/understand (its more likely I don’t know…) so if anyone could explain, I will be extremely grateful!
Thanks,
Meep

“[U]St st[/U], [U]then cut yarn and run through all sts, pulling together tightly[/U]. “
St st means stockinette stitch, which is knit one row, purl one row. When you reach the length specified, you cut the yarn, and thread the tail like a drawstring through the stitches while they’re still on the needle, remove the needle and pull them tight.
”[U]Work in garter stitch for 5 rows[/U] and then [U]BO[/U] all.” ‘Work’ is another term for knit or purl, according to the pattern. Here, you knit ever row for 5 rows (garter stitch) and bind off (or cast off) all stitches.
"[U]Work 2 sts together at the end of each of the next 3 rows[/U]. " Work as in knit or purl. On one row you k2tog, on the next row you’d p2tog.
Mattress stitch is a way of seaming pieces together and is shown on the Tips page under Finishing. Other terms you may not know are found on that page too, on the Casting Off page, and on the decreases page.

-“Work 5 rows in St st.
Work 2 sts together at the end of each of the next 3 rows. 2 sts remaining. Work those 2 sts together and pull yarn through last st.”

So when it says this I work 5 rows in the stockinette stitch then do I start a new piece or… I don’t know. What does it mean by at the end of each three rows? And I understand what I have to do with the last two stitches, but, once again, where?

-And I found another one… :aww:
“Join cast on and bound off edges together.”

Bound off I get…like cast off, right?..but what does it mean by join cast on?

Please and thanks for the previous help (and in advance!),
:heart:meep

You keep going and do another 5 rows in stockinett, then at the end of the next row knit or purl 2 sts tog. Then at the end of the next row, k or p 2tog, and on the next row. These happen when you’ve worked across the row and you have 2 sts left, knit or purl them tog according to if you’re on a knit or a purl row.

The join bound off and cast on edges together means you sew them together.