I have been using Airtable and excel before so in it we will be able to sum the total of the particular cell in one column as we can mention total at last row.
But here i am unable to find the option going throw the documentation and something i am missing kindly help me. I know python too so not a issue but its bit confusing how to achieve it as a newbie.
How do i get a total of this column. its already in formula because i had to evaluate it from other columns.
Hello Rohnak! Welcome to the community. 
The best way to calculate sums of columns in Grist is with summary tables.
Tl;dr:
Click on Add New > Select either New Page or Add Widget to Page > Select the table you wish to summarize > Click the sigma icon (ÎŁ) to summarize the table > (Optional) Select one or more columns by which to group data.
In the summary table, all numeric columns are automatically summed. You’ll also receive a “count” column by default which counts the total number of records in each group.
Sum of values in different tables
If you’re looking for a way to sum values in two different tables into a third table, this thread may be helpful: How do I Calculate Sums from multiple tables to a widget?
Thank you for the response