Ok so im trying to tab this song out i wrote, just the strumming part i do which is really simple, for some reason i cant figure out how to tab it to sound right in guitar pro.

Just 4/4 time, strumming goes like 1-2-3 1-2-3 1-2

Then another bar of the same, i dont know if thats too vague to figure out, just i cant get the note lengths to fit what im doing.

Can someone help out?
Do you mean how the strums are grouped, beat-wise? If so, use the ones on the top here: