The United Commonwealth Army is a full volunteer force, made up of full time professionals, with a large amount of trained reserves that it can call upon in time of crisis.
However, I have been having trouble with connecting the trained soldier to the actual formations that are deployed. On Earth, I know that the regimental system, where soldiers are assigned to battalions in regiments, which are then amalgamated into brigades. However, the world I made has its regiments as a frontline unit, replacing brigades.
One important thing is that soldiers recruited in one place that are not reserved will often be sent to deployments far away from their home countries, often deployed in foreign allied countries for a long time.
My current theoretical system involves splitting recruits into companies, which are then assigned to various pre-existing battalions already deployed, which assist in training and providing the experience needed. In this arrangement, each maneuver regiment will have 3-4 combat battalions, each with 3-4 companies of either armour or infantry troops, of which one will be made up of the relatively fresh recruits.
However, I imagine there might be some problems with this. Hence, I was hoping to get some recommendations as to how a large professional Army would go about recruitment.
The World is a mixture of highly modern technology, slightly better than on earth
The countries are very much democracies, ranging from constitutional monarchy to republics, with a wide variety of human cultures.
Funding is very high, with a minimum 3% of the total GDP of all of the dozens of member nations being chipped in
Nations have surrendered their military control to the central UC Army/Navy, while still retaining combined control over the armed forces' use via the Armed Forces Council, similar to the Atlantic Council in NATO, and the Council of Nations, made up with the heads of state of the countries.
Poverty is generally lower than on Earth, as all of the UC nations are developed or developing quickly.
Military traditions run deep in many countries, especially in the Weslich Empire, where the bulk of the troops come from.