You are going to need an attorney's help on this. If the will provides for the same result as if the decedent had died without will, it may be simpler for your attorney to ask that the estate be administered under the laws of intestate succession. If the will provides for a different result that if there were no will, you will need an attorney to answer how to proceed.
This will depend on your state's laws, but every executor serving under a will in VA has to "post bond." This is usually nothing more than taking an oath to faithfully and fully administer the estate and protect the beneficiaries' interests. Unless it is waived in the will, executors also have to get surety on their bond, which is an insurance policy that backs up the executor's faithful performance. Premiums are paid by the estate. If the executor turns out to be a crook, the idea is that the insurance kicks in to try to make the beneficiaries whole. Many folks waive this insurance requirement if family is serving as executor.
Disclaimer: I am a VA attorney and only licensed in that state. This answer does not constitute legal advice, as each situation is dependent on its own set of facts and circumstances. Nothing in this answer creates an attorney-client relationship.
You will need an attorney to assist you with this. There are several facts which the attorney will need to tell you how involved the probate will be. This forum is great for getting started and general information but for a fact sensitive case such as the one it seems you have it is essential to sit down with a competent attorney to get you off on the right foot.
The will can tell a lot, for instance how many beneficiaries are there and how is the estate distributed. Common sense dictates that the more money and real property at stake the more the bond will be and the more likely the beneficiaries will have issues with how the estate is handled.
One last thing, does the will have the name of the attorney who prepared it somewhere on the document. Contact that attorney if it does to see if he or she might have the original. While I do not advise it, some attorneys hold the original for the clients. If you have not investigated that possibility, start there.
The best to you as you try to untangle this issue and my condolences on your loss.