6They went through the region of Phrygia and Galatia; they had been forbidden by the Holy Spirit to speak the word in Asia. 7When they came to Mysia, they tried to go into Bithynia, but the Spirit of Jesus did not allow them. Acts 16:6–7 (CSB)
Romans tells us that Paul had a desire to preach the gospel in places where it had not yet been preached (Rom 15:20). I'm not sure how he chose what places to go next, but I imagine there was a system. Perhaps they laid out a map and checked off locations until they preached the gospel in each city. I imagine there were logistical issues when planning when and where to go. In this passage, they made plans to go to Asia, but they were prevented by God. The text isn't clear how they were prevented, but I'm sure these roadblocks were frustrating at the moment. It isn't until verse 9 that we realize God slowed them down so they would go to Macedonia.
Paul was called in a dream by a Macedonian man, and while God had stopped them from heading to Asia, God made a way for them to get to Macedonia. And it's a good thing too! On the way to Macedonia, they met an influential businesswoman named Lydia who almost definitely helped launch the churches in Philippi and Thyatira. Then they met an influential Roman official who followed Christ with his family. Interestingly, their actual ministry in Macedonia was underwhelming, but Paul never seemed to regret it. He was in alignment with whatever God wanted... even if it meant modest results.
Sometimes God will speak through our circumstances. Your finances, opportunities, location, talents, etc. may not allow you to do things for God. Sometimes everything lines up, and you have no choice but to follow and take a certain heavenly assignment. Yet, other times God speaks despite our circumstances. Everything may line up perfectly, but God says no. Or God tells you to do something where the circumstances do not make sense, yet he makes a way.
Ok, what's the point? Whatever or wherever God does or doesn't call you is less important than deep communion with him. We don't see Paul fretting over ruined plans or even mediocre ministry. He was so in sync with God's heart that God's presence was his good (Psalm 73:28).
While a clear step-by-step five-year plan for God's will would be so nice, you probably won't receive that in your inbox tomorrow. Yet, God is always with you, and what is the most important thing for you? Be with him. If God sends you to the jungles of Brazil to preach the gospel, do it with him and through his power. If he calls you to work a 9-5, faithfully serve a small local church, and be a witness in your personal mission field, do it with him and through his power. Less important than a step-by-step guide from God is communion and obedience to him.