Before changing your primary field we recommend that you first create a new, empty field in order to paste over the values currently in the primary field. This is because the primary field is unique and serves as the key identifier of each record. This also means that the primary field cannot be deleted.
For this reason, you can't make another column the primary field simply by trying to change its field order into first position. Instead, you'd have to move the current content out of the primary field into a newly created field.
You can create a new field by clicking the plus sign located just after the last visible field in your table.
Then, click the primary field header cell to select all cells in the column, then use Ctrlx (x on Mac) to cut those cell values. Next, you'll paste those values (Ctrlv/v) into the newly created field.
Changing the primary field
When you're ready to change the primary field to a different field type, click on the arrow next to the field name and select "Customize field type". You can then designate a new field type and start entering data. Note that you can't delete the primary field, or create a new one; only the field type can be adjusted.
The primary field does not support attachment, checkbox, single select, multiple select, rollup, lookup, and count fields, or links to other records.
Deleting a field
In case you need to delete a field (other than the primary field) you can do so by right click the field name of the field you'd like to delete. Then select the "Delete" option.