Lets say you were on a journey, two things are already in place
(1) The destination
(2) What to do when you get there.
FAITH is the active expression of these two things right now even before you get there. For example: You would not sit down on the bus and start saying "what if the driver was taking us to the wrong place" No! You were relax and confident without any sense of doubts. Instead of questioning everyone in the bus "Do you really think this driver knows where we are going?". You were calling family and friends telling them exactly what time to expect your arrival. Now that is a big picture of what in action is all about.
The scriptures declares " Now faith is the substance of things hoped for, the evidence of things not seen". (Hebrews 11:1).
Two words were associated with the description of faith in this scripture : "Substance and Evidence" both of them have something to do with the future. "...things hope for, ....things not seen".
Therefore faith has a definite shape, it is tangible, it is "the substance and the evidence", but it's reality is in your heart. The destination is already painted crystal clear in your heart, You can tell how streets are routed, you can give a detailed description of the streets lights and road signs, even the coffee shop cannot be missing in your description. The evidence of been there even while you still in the journey.
You create the end point even before stepping into it. If someone in the bus should ask you have ever been there, you would say here are my house keys in that city. The Word of God becomes your evidence, you have come to believe in the efficacy of The Word.
Your response to the doubt becomes "...It is here and now" when no one is seeing it, you are already living it; You declaring it and giving thanks.
The scriptures declares " but the righteousness which is of faith speaketh on this wise "Say not in thine heart, who shall ascend into the heaven? (that is to bring Christ down) or who shall descend into the deep? (that is to bring Christ again from the dead.) but saith it? The word is nigh thee, even in thy mouth and in thy heart. that is, the word of faith which we preach" (Romans 10:6-8)
You no longer ask the questions "How?" but you start the saying "It is here and Now". The duration from when the journey began to when you get to the destination is dependent on how you build your evidence and the substance.