I can't really give any advice specific to League 2 as I hadrly ever manage teams below League 1 but I can offer general advice on how to get back to winning ways.
If you could post some screenshots of your current squad and tactics and that would be helpful though as there's no point telling you to play a certain formation if you don't have the players to do it.
My first step when taking over a team that can't seem to win is to actually stop trying to win. I know this sounds odd but you should just go for damage limitation and try to focus on not conceding initially. A goalless draw is better than aloss.
Chances are that your players morale is quite low so when you try to score goals you leave yourself open to counter attacks. If the opposition then scores from this you're players will just want to give up because their morale is low. Try to play a defensive formation and defensive tactics e.g. 4-1-4-1 with all defenders and the DM set to defend and everyone else except the striker on support. Play narrower and with a slightly higher defensive line (but not too high) to restrict space. Set instructions to retain posseion and work ball into box and have your starting strategy as standard rather than counter or defensive. Counter and defensive mean you're sitting back and allowing them to attack. Standard but with a defensive formation will mean you're not sitting back or attacking, just trying to win the ball back from them and keeping it.
It may take a while but you should eventually perform better defensively and make sure you praise the players more often. A squad of average players with high morale is better than a squad of good players with bad morale.
From there you could then change to 4-5-1 with wingers and 1 CM on attack to provide more support to the striker and may start to grab a 1-0 win every couple of games. If this is decent enough for you stick with it until you can get some better players. Once morale is better and you trust the defense enough change to a more balanced formation like 4-4-2 and try to control games from the start.
Of course it all depends on what players you have available to you. If you're players are terrible then this will be much harder than it sounds.
For league 2 you'll obviously need different players to those in say the Premiership or even the Championship.
Specifically;
CB's should have good concentration, marking, heading, strength and if possible pace. League 2 attackers are less likely to pass around you or dazzle you with dribbling. Long balls are probably going to be the main attacking method so if your CBs are marking well, paying attention and are good physically they should be pretty good even if their tackling isn't that great.
You should definitley have a fast striker playing as a poacher. Defenders are rarely fast at this level and if you have a fast striker (even with poor finishing) they should get enough chances that they'll be able to put away at least 1 per game. Pacy wingers with good dribbling are also really useful.