1. How to install the Forex Robot (EA)?

Download the link bellow to find the guideline:

https://drive.google.com/uc?export=download&id=1D45xkVAKkHZAKpGoLcwbscPzFZmnwSLj

2. What is Forex Robot/EA with DLL (DLL Version)?

This EA need additional steps when you install. Basically, need to copy DLL file into your root Metatrader and may need to do additional steps. The guideline is in the link above.

Note (Important):
If the product using custom DLL
Some antivirus may block it and flag it as a virus which is NOT.
You need to make your antivirus “allow it”
Its a false alarm and its SAFE ,this false alarm is triggered because this is a custom DLL and not verified to any publisher but need to make this product unlocked.

3. Can I use Forex Robot (EA) MT4 in MT5 platform?

No. It’s two different platform.

4. Can I use High Frequency Trading (HFT) EA in FTMO?

No. FTMO not allowed HFT. You need to check with Prop Firm/Brokers whether can use HFT or not.