The Bible itself asserts that it has been written to be understandable to the ordinary person who reads it.
The entrance of thy words giveth light; it giveth understanding unto the simple. Psalm 119:130
Jesus Christ Himself clearly assumed and asserted that even the most difficult texts of Scripture were understandable to the ordinary reader.
When ye therefore shall see the abomination of desolation, spoken of by Daniel the prophet, stand in the holy place, (whoso readeth let him understand:) Matthew 24:15
Bible study must be independent. Independent of what? Independent of what any author, teacher, religious leader, or human institution says about the Bible.
Only by studying the Bible itself by yourself can you be sure to learn what the Bible teaches, unswayed and uninfluenced by sources outside the Bible. Only this way can you be sure to get at the heart of the truth the Bible was written to convey.
The Bible is an understandable book. It was written to be understood. The first step in real Bible study is to read a plain text edition of the Bible to learn from the Bible alone what it teaches.