The Apostles doctrine, the signs of the indwelling of the Holy spirit.

 The  Pentecostal path  to salvation to the best of my understanding is to first 

1. Believe upon the Lord and  come into repentance for your  sins

2. Be baptized in the name of Jesus Christ 

3. Be filled with the power of the Holy Ghost  /receive the evidence of it's indwelling

I will say 2 and three can happen with the order swapped because that's how it went for me . I believe that's fine as long as you have all three steps ,

The Bible does address that physical signs will be there for those that believe on Jesus .

it's stated very clearly in Mark chapter 16 verses  15-17-18 .

15 And he said unto them, Go ye into all the world, and preach the gospel to every creature.

17 And these signs shall follow them that believe; In my name shall they cast out devils; they shall speak with new tongues; 18 They shall take up serpents; and if they drink any deadly thing, it shall not hurt them; they shall lay hands on the sick, and they shall recover.

Those who the lord had told  these things also looked for the  physical signs of the Holy Ghosts indwelling    stated in verses 19-20.

19 So then after the Lord had spoken unto them, he was received up into heaven, and sat on the right hand of God.

20 And they went forth, and preached everywhere, the Lord working with them, and confirming the word with signs following. Amen.

I received the evidence of speaking in Tounges through faith in the Lord firstly, But I also tarried to see the sign of faith ,and it was given.  Tarrying means to wait, and seek the baptism of the holy spirit , I did so  while repeatedly  calling upon the name of Jesus ,and was eventually filled with the holy spirit ,  And given the evidence of Tounges , you can try tarrying in this way for  yourself or pray for it , but the way I explained  is the way me and many others searched for the physical, sign of faith and received it while doing so you must have faith it can happen.

This was something i'd always wanted to be able to explain when I came across people online that needed this information but I didn't have the capacity to gather my thoughts and explain it

all at once to them, and many times it would go over the amount of characters allowed when I did attempted to type it out . And one last thing after this is done there is still a long path ahead In holiness. You will  have to let go of some things if they are sin once you come into the knowledge of it . In some cases  even when they aren't sin on their  own but are becoming idolized by you  . But with the process  I mentioned earlier completed . You will know your soul has been saved.  And from there  you should as a servant of God live according to his word . 

oh  and one last thing for real this time . If you try the tarrying I mentioned earlier , and your lips start to stammer continue you are getting closer.  I also did the same before I began to start speaking in Tounges .