Step by Step procedure for construction of building foundation on an organised construction site can be as below:

1. First step is to write a method statement involving scope of work, references, count and type equipments and labour required and requirements .
2. Ensure you have  approved drawings good for construction
3. Prepare BBS for foundations and order reinforcement and ensure materials are on site and correctly stored.
4. Request survey department to mark foundation centrelines and sizes including working space.
5. Perform excavation manually or using machines depending on depth, nature of soil and water table. Some time you may to resort to dewatring to keep the water well below the foundation level.
6. Do not over excavate . Any over excavation should be made top by lean concrete.
7. Do not expose the foundation level for long time time. Ensure lean concrete is poured as soon as foundation level is reached .
8. Inspect the foundation level for loose material or soft patches.
9. Lean concrete is normally 75mm in thickness
10. Following PCC or lean concrete, install reinforcement including column reinforcement or dowels and shutter the foundation. Use concrete covers of required size at the bottom and sides of reinforcement.
11. In Middle East they introduce waterproof membranes ( refer: Grace Products)on lean concrete which raps the entire foundation as protection ( also known as tanking)
12. Once the rebar is in place , with cover you need dust off and get the foundation inspected.
13. Concrete Pour Card provides you all the checks you need to perform before casting foundations.
14. You order correct grade concrete + check slump+temperature before concrete is allowed to be poured.
15. Compact the concrete in layers using vibrators without leading to segregation.
16. Cast the cubes to test at 7 and 28 days
17. Cure the cast concrete for minimum of 10 days if it is wet curing
18. Deshuttering of vertical faces is normally 24 hour to 48 hours.
19. Once deshuttered and cured foundation is provided with coating or membrane protection.
20. Finally foundations are backfilled by selected approved fill material in layers of 200mm or less to 95% degree.

Hope this helps.