Line 3 is telling you how to translate your results into Yasko's notation, but isn't saying anything about what's normal. So for COMT 4680, line 3 says +A/-G. This means that you should put down a + for each A or T you have at that SNP, and put down a - for each G or C.
So if your SNP is AA, then you mark it down as +/+. If you are AG, then you are +/-. If you are GG, then you are -/-. And, as you mentioned earlier, A=T and G=C.