It's best to give bub new solids during the day so you can watch easier for reactions (but this mostly affects people with family history but you can never be too careful) So breaky and lunch is best to start at. Bubs don't know the time of day so you can always give them vegies for breaky if it's easier.
At 4 months vegies like potato, pumpkin, sweet potato, carrots and zucchini are good starters. And apples, pears and bananas are good ones to start with. Just watch apple as it can constipate as can green banana. As a rule fruits and veg that start with "P" help bubs poo. Bananas can be give fresh but everything else it's best to cook (if you want homemade) Pears and apples just peel, core and boil in a little water. Vegies peel and steam to keep their nutrients. Puree with a stick/hand blender or food processor except for potato. It turns to "glue" and taste like crap coz it's got too much starch, just mash it really well.
Start off with small meals 1-2 tablespoons and single foods at first to help make it easier to know which one bub re-acts with if they do.
I've been told it's best to always give bub their milk feed first up until 9 months as this is their most important food as it contains everything they need and food at this age is mainly to help them go the distance between feeds easier. The only meal I have always give Jeb before milk is his tea and it was at least 1.5 hours before so he'd still have all his bedtime milk. I have only just swapped all his feeds around now and he's 9.5 months.
Hope all my ramblings help a little....I know what it's like first starting bub on solids and not knowing if you're doing things right, but bub will let you know if he's not happy. Good luck smile