I have been a vim user for a long time (actually I am using spacemacs with vim keybindings, but nevermind). But I have never really used the registers, which is really bad, since it made my workflow less fluent.

So I found this stackoverflow question, which explained it very well: http://stackoverflow.com/questions/1497958/how-do-i-use-vim-registers

What I basically grabbed from the post was this: To yank, prefix a yank with "k where ‘k’ is the register name. To paste preface the paste with "k where, once again, ‘k’ is the register name.

So to copy the following line into register a i would type "ayy and to paste it again I would type "ap