Hi!
I am fairly new to knitting and so far have learned everything i know on the internet! one thing I don’t know is how and where to place markers? also do you have to buy special knitting markers or can you use a common household item (like a paperclip or safetey pin?) also what does slip marker mean? thanks for your help!
Placing markers
You can use a safety pin, paper clip, loop of different colored yarn, whatever will fit around the needle. Most markers are put on the needle to mark off a section of knitting where you might be doing increases or decreases. To `slip marker’ is to move them from left to right needle when you come to them so they travel up your work as you knit. Sometimes you’ll see a direction to put markers at each end of the row. These go in the end stitches and stay there, and are used so you can measure up from that point.
The thing that makes so many people slap their foreheads and go “duh” is that the markers go on the needles, not IN the stitches but between them, and just go back and forth to keep your place. A lot of people who have mentioned it try to knit them into their stitches the first time or so. 
You can also use them for pattern repeats so you don’t lose your way. For instance, if a pattern is to be repeated every 10 stitches you could put a marker every 10 sitches to know when to repeat and it also helps to notice mistakes quicker.