I can give you a very high level overview. I have a friend who is a lidar guru and he does all the detail work, so I can't give you specific links.
I will say one thing about it -- you can see old roads in the lidar data that you cannot see in the field, aerials, or are not on maps. For that aspect, it is really cool. We have discovered a road in my area than is not on any map or aerial I know, and I have successfully detected, finding about 25 coppers. It also should work for features like celler holes, old walls that are gone, and other man made features that are not obvious in the field.
Anyway, here is the high level view, someone with more details can chime in.
Basically, there are two components, the returns and the reader. The returns are the actual lidar data. This is almost always public domain, and you have to google for the returns for the area you are interested in. Some states, counties, universities and the like have this online, the trick is googling for the data for the area of interest, Then you can just download the data or read it online, depending on how the site is set up.
Next is the reader. These are public domain/open source clients that visually render the data so you can see the features in the terrain. Once you get one set up, it generally works for most lidar data out there. My friend has a standalone client, tho likely there are web based clients out there now.
That is about all there is too it at a very high level. Start with the area of interest, then google for the returns (usually by county or town or GPS). Then google for a reader that reads it. The site with the returns often has a link to a reader client.
HTH, tho it may not be at the level you are interested in.