Hi, I need help! Please kindly advise on how to properly calculate a home loan. My family and I are looking at a DBS home loan (cont. in details)?

Example of intended borrowing principal $375,000
Looking at 10 year loan
First 5 years, 1.5% p.a.
Next 5 years, FHR24 + 0.90% p.a. (all-in 1.80% p.a.)

How do I find out a more accurate monthly instalment for this loan?

I tried using online calculators but was only able to generate a fixed rate for 10 years, so the monthly instalments are not accurate.

Please help! Thank you very much!