There will be 3 rounds. In 1st round they will give you a test paper which will contains aptitude questions, reasoning, etc after that they will give you another paper which will contain some salesforce theoretical based questions. Also, first round will be a formality for an experienced person. In second round, they will ask you to write a simple trigger in 1 hour. Some trigger examples are - Populate recent contact's dob on its account (insert, update, delete, undelete), Populate max and min salary of contacts to its account (insert, update, delete, undelete). You may be asked to write a code for vf page too. 3rd round will be managerial round in that you'll be asked to share about yourself, your projects, how did you implement them. Also, you'll be asked some admin questions like Security in salesforce, etc.