How to access inner Link Field in Frappe

Good day,
I have a Link field called m_aid, so i want to go to it’s doc type check if the field c_processor is equal to something then i update my current field.
Here is my code

frappe.ui.form.on('Claim', {
	setup: function(frm) {
	p_instruction: function(frm) {
		if (frm.doc.m_aid.c_processor == 'MOD') {
            frm.set_value({
                p_instruction: 'MIP',
            })
        
		}
	}	
	
});

use below

frappe.db.get_value("Link Doctype", "doc.link_fieldname_in_current_doctype" ,"value_to_fetch_from_linkfield_doctype_field"

Hey @mohitchechani, thank u, but i have done my code as below and nothing happens.

    		if (frappe.db.get_value('MACO', 'frm.doc. m_aid', 'c_processor') == "MOD") {
                frm.set_value({
                    payment_instruction: 'MIP',
                })
            
    		}

use it like this javascript

    frappe.db.get_value("User", frappe.session.user, "mobile_no").then(function(r) {
        var mobile = r.message.mobile_no;

I want to put it in setup function

	setup: function(frm) {
	    if(frm.doc.p_instruction == ''){
    		if (frappe.db.get_value('MOD', 'frm.doc.m_aid', 'c_processor') == "MIP") {
                frm.set_value({
                    p_instruction: 'MIP',
                })
            
    		}
	        
	    }
	},