Store Data From One Table In Another Table

I am a beginner working with access (2013). I am looking for a way to retrieve data from one table and store these values in a other table. The tables are in the same database.

For example:
Table 1
Input [OrderNr]
Input [Nr] (linked to Table 2 [ID]
Input [Amount]
From Table 2
Get [Product]

Get [Unit]
Get [Price]
[TotalPrice] =[Amount] * [Price]

The result should be wiewed as a datasheet.

Problem 1
I have made the form and the links between the tables and it works alright on screen. Except the sum-function It does not work. I can only get the amount of items in the summery field for column TotalPrice. Is it because it is a column for calculated values? Other columns including not calculated numeric values works alright with the sum-function.

Problem 2
The data from table2 will not be stored in table 1