The Coming of the Lord Jesus Christ in the air is described for us in 1Thessalonians 4:13-18 But I would not have you to be ignorant, brethren, concerning them which are asleep, that ye sorrow not, even as others which have no hope. 14 For if we believe that Jesus died and rose again, even so them also which sleep in Jesus will God bring with him. 15 For this we say unto you by the word of the Lord, that we which are alive and remain unto the coming of the Lord shall not prevent them which are asleep. 16 For the Lord himself shall descend from heaven with a shout, with the voice of the archangel, and with the trump of God: and the dead in Christ shall rise first: 17 Then we which are alive and remain shall be caught up together with them in the clouds, to meet the Lord in the air: and so shall we ever be with the Lord. 18 Wherefore comfort one another with these words.
Dr. Manfred Kober was a Professor for many years at Faith Baptist Bible College in Ankeny, Iowa. His four page paper for the Faith Pulpit is worth a read at https://www.manfredkober.com/materials/FP/1988_1001_How%20Soon%20the%20Rapture.pdf.
If you do not know what the Gospel is Paul gives forth the Gospel in 1Corinthians 15:1- 11 ¶ Moreover, brethren, I declare unto you the gospel which I preached unto you, which also ye have received, and wherein ye stand; 2 By which also ye are saved, if ye keep in memory what I preached unto you, unless ye have believed in vain. 3 For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; 4 And that he was buried, and that he rose again the third day according to the scriptures: 5 And that he was seen of Cephas, then of the twelve: 6 After that, he was seen of above five hundred brethren at once; of whom the greater part remain unto this present, but some are fallen asleep. 7 After that, he was seen of James; then of all the apostles. 8 And last of all he was seen of me also, as of one born out of due time. 9 For I am the least of the apostles, that am not meet to be called an apostle, because I persecuted the church of God. 10 But by the grace of God I am what I am: and his grace which was bestowed upon me was not in vain; but I laboured more abundantly than they all: yet not I, but the grace of God which was with me. 11 Therefore whether it were I or they, so we preach, and so ye believed.