The Court of Arbitration for Sport recently found 34 past and present Essendon players guilty of doping during 2012 and imposed season-long bans.

The decision shocked the football world and sent the Bombers scrambling for top-up players among recently retired men from other clubs.

Lawyers for the 34 will lodge paperwork with the Swiss Federal Tribunal, officially launching an appeal against the ban.

Who is involved?

All the 34 past and present players will be part of the last-ditch appeal. Some players were said to be waiting until the last minute to decide whether to get involved, but the entire group has agreed to go ahead with the legal action.

Who is paying?

Essendon's insurance company is covering the costs of the players' legal bid.

What is the Swiss Federal Tribunal?

It is the Federal Supreme Court of Switzerland and the only place where CAS decisions can be appealed. It is based in Lausanne.

What are Essendon players arguing?

Lawyers working with the players have discussed arguing against the Court of Arbitration for Sport's decision on three fronts.

Firstly, they say CAS did not have the right to re-hear the case. Remember, the AFL's own anti-doping tribunal originally found the players not guilty.

The 2010 AFL anti-doping code stated tribunal rulings could only be appealed if the decision involved legal error or gross unreasonableness.

But the updated code, unveiled in January 2015, allowed the World Anti-Doping Agency to tackle the entire case again before CAS. The players say that was unfair because the tribunal had already begun hearing the case when the rule changed.

In a statement on Thursday morning, AFLPA chief Paul Marsh said: "The appeal has been made on the ground that the CAS erred in determining that the WADA appeal should be conducted as a de novo hearing. That is, WADA should only have been allowed to appeal the unanimous decision of the AFL Anti-Doping Tribunal on grounds of either legal error or that it was grossly unreasonable."

Secondly, players say CAS did not consider the players' arguments on a case-by-case basis, and thirdly, they say the penalty the players were given is unreasonable.

Does this mean the players remaining at the club can appear for the Bombers this year?

No. The players have not asked for their suspensions to be put on hold while the appeal takes place.

"It's important to note that the players have not sought an injunction to cause a stay of the CAS decision, meaning they will remain suspended until the Swiss Federal Supreme Court has considered and determined this matter," Marsh said.

So what's the point, then?

No athlete wants to be remembered as a drug cheat and the Essendon 34 want to clear their names. "The appeal is not about an immediate return to football for the players involved, but rather it is about obtaining a just outcome and clearing their name," Marsh said.

Captain Jobe Watson won the Brownlow Medal in 2012 and the AFL has not yet decided whether he can keep it. If the players' appeal is successful it seems likely he will be able to hang on to the honour.

Are the players likely to win?

This is one of the known unknowns, as Donald Rumsfeld would say.

The players have been given advice from a number of lawyers and have reportedly been told they have a reasonable chance of success.

Does the Swiss Federal Tribunal uphold appeals against CAS decisions very often?

No, it's rare. But it has happened. In 2012 the tribunal struck down CAS' decision to impose an unlimited, worldwide ban on Brazilian soccer player Matuzalem Francelino da Silva taking part in any soccer-related activities. His case related to a contract breach, not doping charges.

When will the Essendon appeal start?

No date has been set, but it is not expected to begin for several months at least.

"We expect to be advised by the Court on the next procedural steps, including key timings involved in the appeal process," Marsh said.

Can we watch?

Even if the proceedings are open to the public, video cameras will not be allowed inside.