I'm trying to gain readmission back to a major that I got discontinued in, I received tips to see the department chair, any other advice?

Yes, you should talk to your former academic adviser before you talk to chairperson of the Department.  Anyone saying an academic adviser does not know the requirements for ad.ission or readmission obviously has no idea what they are talking about. 

If the?department chairman has changed in the year that you have been absent, talking to your academic adviser OR someone on the staff is even more important. 

I dropped out of graduate school for 7 years. When I went back to school as a non degree seeking continuing education student. After year I became a degree seeking undergraduate. I. That case I DID go to an associate dean because the progress I took one class from was the acting dean of the college. I knew WHO to talk to. I told the associate dean I wanted to major in physical geography. I earned a third bachelors degree in 2 semesters. Then I decided to go back to graduate school. By that time is was 9 years since I had dropped out. I talked to the secretary who advised graduate students. The chairman of that school and department had changed. I had not met him, but he obviously knew my history from other staff members. I told him what type of masters thesis I wanted to do. He?asked me if I had a particular study area in mind. I told him no. I was admitted pretty quickly. Because I had been gone over 5 years, or, in this case 6 years. none of my graduate credit from the first master's program counted. I had to start over again. For various?reasons. Including the death of my father after 2 years and I was usually enrolled part time, it took me 6 years to earn the masters degree. I was. my.advisers last graduate student. 

Get into contact with your academic adviser. Make?an appointment. Wear a mask if you see anyone face to face. 

Good luck. 

Your old advisor might not know the answers to your questions.  That's why you were told to see a department chair, dean, or associate dean.  Faculty members and advisors don't have the authority to grant you readmission, and may not even be aware of the requirements for readmission.  There really aren't any "tips" to help you in this situation.  Contact the department chair, dean, or associate dean as you've been instructed, and provide them with the necessary or requested documentation for review. There's no reason to start the process anywhere else, and doing so will likely just draw it all out even longer than necessary. 

EDIT: Many advisors are faculty members who really do not know the details of readmission, nor do they have the authority to tell a student whether they would be readmitted or not.  I am the director of advising for my department, and I know enough to know that there are MANY factors that go into readmission.  I wouldn't be able to tell a student anything.  Other departments use staff advisors, and they are also not given such latitude.  So speaking to someone higher up is to your benefit, as they are the ones who know the details and can make the decisions.

you're doing fine.  continue along this path

Your message is not clear.  If you have been "absent and undeclared for more than a year," are you even still enrolled at this university?  Were you dismissed from this major due to academic reasons, and then went somewhere else to try to make up credits?  Who told you to see the department chair, dean, or associate dean?  Was it a university official who told you that, or random people you know?  I would say you should first verify your continued enrollment at the school.  If you are enrolled, then apply for readmission to your major.