I always use vaseline on parts that are going internal like that.
Make sure that the mating surfaces are clean and dry, use some RTV black sealer to hold the gasket onto the pump, nothing between the gasket and the block. (that way you can get the pump back off without problems)
I always use new bolts when replacing parts, cause the old ones get stretched threads, and new lock washers as well. Tighten the pump to the block before you attempt to attach the lines. Use teflon thread tape on the fittings that go into the new pump.
That should be about it. Its an easy swap.