Translation:Selamat datang, silakan.
There are several "please" words in Indonesian, unlike in English.
If you want to invite with respect someone to do something (please come in), you use "silakan" (very well translated with the French "je vous en prie"). Also if someone ask you if they can do something, and you accept and want to tell this person very politely.
if you rather ask respectfully someone because you want to do something, or you want a service from this person, you use "tolong". For instance, if you want someone to help you to do something.
But I'm not sure there's the idea of coming in in the Indonesian sentence "selamat datang"? Literally it's "good coming". Is it a prayer than the host makes to the guest to accept the respectful greeting of "good coming"? In this case, the "silakan" would be badly translated in English, isn't it?
And, also, is the English sentence really natural here?
You mean "welcome" is sometimes "selamat datang", and sometimes "sama-sama"/Terima kasih kembali.
It's explained in other messages. Welcome, when you come in my house, it's "selamat datang" (literally good/happy coming)
And "you are welcome" when you told me "Thank you", oh it's nothing, you are welcome. It's sama-sama/terima kasih kembali.