Filing itr for salaried professional with other investments

Given that LTCG is now taxed, how could I calculate that?

Not for FY 2017-18......... it is tax exempt till all the transactions upto 31.03.2018.

What ITR Form do I need file?

ITR 3 in case of normal process. Otherwise ITR 4 if intraday gains can be declared under presumptive assessment. (The forms may change for AY 2018-19, the suggestion is based on AY 2017-18)

What steps do I need to follow to file the income tax on cleartax?

They provide paid service, if required.

Should I be taking assistance from a CA to file my ITR? If so, what would it be for?

Depends upon your experience in handling such job. Better to get help whenever any doubt.......
 

Thanks for the reply.

1. Are there any trainings or youtube video series that can help me to file my ITR myself?

2. What more is needed to calculate the tax apart from calculating the short term capital gain and intraday gain/loss?
 

Refer: 1. filing_your_income_tax_returns_online

2.    eFiling/Registration_Services

3.   e-filing_ITR_hbook

Thanks for the reply. I will go over the links. Any comments on the 2nd point?

All the income whether taxable or not is to be considered, as explained through the links.

Non-taxable will be disclosed under schedule EI, while taxable are disclosed under 5 heads........