Being use

I have some confusion over the use of “being”.

I know I can use being while changing the voice. For example: He is doing the work (Active voice). In passive voice, it would be The work is being done by him.

Now my question is, how can I use ‘being’ as a participle. For example

Being a nationalist means - Is it grammatically right? If yes, then please tell me here 'being" acts as a participle. Also, I want to know whether there is any basic difference between being and as Like As a nationalist, I love my country and being a nationalist, I love my country. Please help me to understand being.

“Being a nationalist means…”

When you are using it like this, you are using it as a ‘gerund’ (i.e. a verb acting as a noun).

“Keeping fit is very important” = ‘Keeping fit’ is the subject and ‘keeping’ is a gerund.

"Being kind is very important’ = ‘Being’ is a gerund i.e. turning the verb ‘be’ into a noun.

A gerund is a present participle (a verb with ‘ing’ added).

I’m not too sure about your second point, but you can use ‘as’ instead. For example,

As an active member of the Labour party, I go to all their party conferences.

You could substitute ‘as’ with ‘being’ in this sentence without changing the meaning.