This is the most difficult part. it is even difficult (nearly impossible) to explain in a post.
But i will give you some hints.
first of all we have to find out the financial reports for last few years.
then we should compile information from those reports and arrange them.
at this point we have to adjust some values as well (ex: assume that in report it says NAV is 250, but if we know that they have non performing assets it is up to you to readjust the NAV or go ahead with given NAV).
you have to forecast the future value based on your knowledge about that sector and company and economy.
then valuate at least based on two models. and match it with the other companies in the same sector and adjust it accordingly.
I know that above description doesn't help you.
first study the valuation model theoretical part.
there are YouTube videos which teach you the above method in detail. just search , there are lot of videos.
example : https://www.youtube.com/watch?v=ugnXFpiUsYo
once you are ok with that knowledge,
just go through this video (LIOC share valuation by equity plus)
Then you will understand still there are values that we should forecast.
Then what should be done is , calculate 3 values (low growth , average, high growth).
So if you calculate the value and i calculate the value, then there will be two values, because we give different weights to different factors when we forecast values.
Then try out your self.