The best thing you can do is to enjoy being with him. That way you'll naturally involve him in your activities. Toddlers love to help and be involved with mommy or daddy. The learning at this stage will happen as you two just do life together. Talk to him, hand him things, ask him to get you things, tickle him, roll around, hide under a blanket, etc.
To bolster that, give him dedicated "slots" in the day where you read a book together or play with a couple of toys, just for his sake. Your day is bound to fill up with to-dos, so you need to strike a balance. But, if he's involved in your day, and helping, parenting is a lot more fun and he'll benefit from morning till evening as you two do it together.
Also, do not compare him with your perfect sister/colleague/neighbour whose child was walking at 8 months and plays the violin at 2. The most important things our three get is love and prayer and they are all flourishing. All the best!