Hi Nick, and welcome
no forgiveness needed, we all start somewhere and asking questions is a good way to learn. Would be a good idea to have a good read through the beginners section and some of the other basic/tutorial type posts as well though, as there is a lot of good stuff in there which can really help to get you head round things if you're starting from zero. But in answer to your question....
The caps with a the +/- on the layouts are usually polarized electrolytics and look like round cans with either a lead at each end (Axial) or two leads on the base (Radial) one of those leads matches a stripe up the side which is the - and is shown on the layouts a s a mark on that edge of the cap
for example on this layout the cap in question is the 47u, and spans rows 1 and 2, with the + on row 1 (Top) and the - on the next row down
http://tagboardeffects.blogspot.com/2012/05/ehx-screaming-bird.htmland even though the colours used are a little bit different in this layput the principle is still the samel. 100uF cap (In the centre, spanning top to bottom rows) + is the top, and the marking for the - is to the bottom
http://tagboardeffects.blogspot.com/2016/11/earthquaker-devices-tentacle.htmlHope this helps