Horsfield Tortoises

Just 10 days ago my brother and I got 4 Horsfield tortoises all around 12 months old, keeping 2 each. One of mine appears to have watery eyes, not eating very much but is lively. One of my brother's makes a hissi sound if you approach him and has tried to bite his finger. Looking at some of the websites there does appear to be alot of difference of opinions and guidance. As we are very new to keeping tortoises any guidance in ensuring we support them correctly would be appreciated.