You probably aren't seeing the reference table EntryLog in Claims filling up as you press the button.

I don't see the line where you link the new EntryLog record with the current Claim record. Sadly Ninox does not automagically link the records. By default Ninox would have created a reference field in EntryLog called Claims. So using that name you need to add two lines:

let t := this;
-previous lines-

newLog.(Claims := t);

If you renamed it then please update the name.

What happens when you use the create() command is that Ninox creates a new record like if you went to that table and clicked on the + sign. You have a new record with empty fields. Now you need to link this new empty record to the Claims record you are on.

So first we need to put the current record you are on into a variable. So line 1, we use the this command to get the current record Id into a variable, the letter t. Then on line 3, you create a new record in EntryLog and put that into the variable newLog. The first thing I do, is then link the record new record with my current record, line 5.

In you second picture, that show E_Log, I see that Claims1 is the name of the reference field to, I guess, the Claims table, if this is not true then you need to make sure you use the name of the reference field. So this is name you need to add to your newLog.

let t := this;

let newLog := (create EntryLog);
newLog.(
    Claims1 := t;
    Payment := t.'Amount Paid';
    Payment_Date := t.'Date of Payment';
    Paid_To := t.'Paid To:';
    Paid_From := t.'Paid From';
    Claim_ID := t.'Claim ID';
    'Date of Claim' := t.'Claim Date';
    Creditor_Name := t.'Creditor:';
)

By using the this command, you have access to all of the fields in the record through the variable. So I've cleaned up the code to show how it can be written.

I also added a formula field to my Claims table named 'Total' and I would like it to group all the payments made grouping them by their Claim id's so I added this code to the field:

sum(select EntryLog where Payment = this)

Your code will not return anything because the this command returns the record ID of the current record. Plus it can only used in limited circumstances, like in setting a variable. So almost all of my code has the same line 1:

let t := this;

I'm guessing you only want to find the total payments of related records. By using the select and only looking at Payments you will get all EntryLogs with the same Payment regardless of which claim it belongs to.

We want to use the power of a relational database that is Ninox. Since you have a M:1 relationship between EntryLog and Claims. Once you solve how to link records in a button, you can simply do something like:

sum(EntryLog.Payments)

in a formula field.

If you continue to have issues, please post a sample DB (with no personal information) to the forum.