Timing seal should go in with a seal driver, but if you don't have one a socket or round piece of hardwood that is close to the outside diameter of the seal will work. On some the seal won't want to start so it may require a little light sandpaper action on the starting edge of the seal so it starts. They coat the seals and sometimes it creates too much interference with the hole. 50/50 if it's an issue or not.

Make sure you don't disturb the thin round spring on the rear of the seal either. Some like to put a little white grease on the backside to keep it from falling out. Not a common thing, but be aware of it.

Cover should go back on with a few bolts to get it suspended initially. There are different lengths and several go into the coolant passages if I recall so you'll need some paste on the ends of some of those bolts that go into the block or you'll have leaks to deal with. If you have the bolt orientation scrambled do a dry run test fit mock up to get them back in the proper order.

Permatex makes antifreeze specific sealers in little tubes for the water pump to timing cover seals. Worth the money vs standard rtv.