meany ways of pushing guides in. you really should use a small press. but sometines you can wind them in with a small bolt going down through the guide to a plate on the head face or even just tap them in if your carefull.
reaming them, reamers are used to accuratly open up holes to specific size and ensure the holes are round, drills can't be used as they just arn't accurate enough.
some valve guides don't need reaming after fitting some do chances are the valve stem will fit though the guide before fitting but after fitting it may not, youve not done anything wrong but as the head is squeezeing the guide and the hole though it becomes slightly undersized ( this is good as it means the guide is held in the head very securely ) a reamer is then used to open up the guide to the exact size required for the valve stem. t'll take feck all metal off can ether be done with a hand reamer or in a battery drill just rember to give the ream a littel oil and they run much slower than drills but with more pressure
