All things were made through him, and without him was not any thing made that was made. John 1:3
You will notice about the apostle John that he often uses quite circular language, making a statement and then restating the same idea with a different nuance. I rather like his style of writing (it really annoys others) because what it often achieves is to differentiate what he is saying from what he is not saying.
In the verse I’m considering here he is making it clear that the Word (Jesus) is the means by which all that exists has been created, but he is not himself created. The Word was in the beginning, he is God, he is not himself a created being (John 1:1-3).
So our perception of Jesus must include knowing him as Creator of all things. To bring it even closer, he created you, and me. It is through Jesus Christ that you exist — to use a circular argument myself, it is impossible for Jesus not to exist because you exist and all things that exist only do so through Jesus Christ (1 Corinthians 8:6). Our continued existence reassures us that Jesus is God. (I know that argument won’t wash with an atheist because it requires trusting that the Bible is the revealed word of God.)
Not only were all things created by Jesus, they were all created for him (Colossians 1:16). In Johannine style, all that is made was made for him. This also takes some getting you head around, all that exists (or has existed) was made for Jesus, even Hitler, even Satan. (Chew on that, but please don’t choke on it — don’t destroy your trust in the goodness of God ( Mark 10:18) for the sake of an intellectual idea.)
Finally, Jesus created all and he will inherit all things (Hebrews 1:2). In this we also know that all things are his to do with as he wills, he has been appointed Judge (Acts 17:31) and he judges in justice and truth (Revelation 16:7). The positive and glorious aspect of Jesus inheriting all things is that he inherits the Church, all the saints, as his bride — this indeed is a profound mystery! (Ephesians 1:18, 5:32).