Salary and LIC agent commission income - Tax implications and ITR form

Employee in Private iT company filing currently ITR 1 

For FY20-21 planning to buy 2nd residential flat and also to become LIC agent. Being first year cannot expect much of commission money from LIC agent. 

My query

1. Which ITR form should I fill ? Can I do myself - any specific guideline/website which guide step by step and mean of each tab ? Can this ITR be applicable for my Salary and LIC commission amount  or should I fill in 2 separate ITR a) one of salary b) other for LIC commission or income if any from 2nd resident property 

2. Tax implications 

 - willl commissions will be deducted for TDS 

- pls the net income will be added to my Salary income and chargeable to tax at applicable tax rates. 

Thanks in advance. 

Thanks

Verun