1991 Other Nissan Models Starting to blow blue smoke

My 1991 Nissan Axxess is starting to blow blue smoke out of the exhaust. I was told it needed a new head gasket. So my question is, how would I go about putting on a new head gasket myself? My husband is use to working on his car so he thinks he should be able to change it on my Axxess. We just need to know how to do this. So any advice you can offer us would be greatly appreciated. Thank you