With clay or concrete pavers, it's usual to lay them on 40-50mm of sand over a compacted hardcore base.
If you want to lay them on concrete, then a simple 10mm bed of sand & cement. The mix isn't terribly important. 3 sand to 1 cement (without plasticiser).............. or 6 to 1 with plasticiser.
For bricklaying.... so many different mixes, but the most popular are 6:1 with plasticiser.......
Or, 6 sand:1 lime: 1 cement
To some extent, it will depend on the type of sand your using. It varies a lot around the country.