This is computer's evaluation of the position. +1,00 means white had the advantage of one pawn (either positional or tactical) and -1,00 that black had such advantage. Note that evaluation includes positional and strategical prospects of position as well as initiative . So you might be a rook down, but you have a superb position and computer evaluates it with, e.g. +2, which means, that with precise play you should recover your material and win approximately two pawns.
In your example, black was slightly better.
Hey I had a game analysed but what do the numbers mean when i click through each move such as (-0.46), and next move might be (-0.44). What do they mean? Thanks, sorry it might sound a bit stupid but im new to this:p